Intermittent drive for sequence switch mechanism



Jan. 1, 1963 1. A. WOOLLEY 3,071,017

INTERMITTENT DRIVE FOR SEQUENCE SWITCH MECHANISM Filed June 50, 1959 2 Sheets-Sheet 1 FIG] FIG-3 INVENTOR.

LEE A. WOOLLEY ATTORNEYS Jan. 1, 1963 1.. A. WOOLLEY 3,071,017

INTERMITTENT DRIVE FOR SEQUENCE SWITCH MECHANISM Filed June 50, 1959 2 Sheets-Sheet 2 38 g I 66 Ma 53 I 23 5' I]! H I 5 2 "#7! ll m I I INVENTOR. LEE A. WOOLLEY TTORNEYS United States Patent Indiana Filed June 30, 1959, Ser. No. 824,085 Claims. (Cl. 74125) This invention relates generally to switch mechanisms, and more specifically to a sequential timer having an improved drive mechanism incorporated therein.

Although the principles of the present invention may be included in various sequential switches, a particularly useful application is made in sequential timers or" the type used to control domestic automatic washing machines. In the control of such machines, numerous circuits are provided which must be closed and opened at preselected points in a washing program. This requires a relatively large number of electrical switches to be used, and to be coordinated with respect to each other by the use of a sequence cam. In order to have sufiicient power to positively rotate the cam in discrete increments, energy must be stored in an intermittent drive mechanism, and periodically released and directed to the sequence cam to advance it in increments. To insure operation of all of the switches contained therein, it is necessary that a substantial amount of energy be stored. However, the presence of an excess amount of energy applied to the sequence cam can also be the cause of a malfunction.

At certain points in the program cam, there will be less drag applied to the program or sequence cam than at other points. In order to handle a relatively large amount of circuits, a relatively large cam is employed. Such a cam has a considerable amount of moment of inertia, so that when it is accelerated by the drive mechanism, and when the resistance to its rotation is at a minimum, there is a tendency for such sequence cam to continue to rotate of its own inertia and after the drive mechanism has reached the limit of travel for that increment.

In order for a timer construction to be commercially successful, it must be adaptable to the changing needs dictated by the addition and removal of washing machine features from year to year, from model to model, and as required by different washing machine manufacturers. One of the features which a timer manufacturer must be prepared to vary is the number of switches provided in the timer. If the weight of parts, strength of springs, and the like is properly selected, the overstepping problem described above can be minimized. However, when the manufacturer is asked to provide timers having a substantially smaller number of switches, the drag applied to the sequence cam is greatly reduced and the overstepping problem again becomes active.

The present invention contemplates a cam-to-cam structure in the drive mechanism to limit or select the acceleration with whichthe sequence cam is periodically ad vanced. The components providing the cam-to-cam relationship are readily removable, so that by a mere substitution of an easily removable part, the problem may be quickly corrected in a particular timer. Further, the structure is so arranged that at the manufacture of various models of timer, the assembler can select one of a number of corresponding components which differ from each other in the amount that the acceleration will ultimately be retarded. The various components making up the improved drive mechanism in this timer are substantially all held in assembled relationship by virtue of their. configuration, and therefore the compensating components can be easily installed, replaced, or exchanged without the use of hand tools.

Accordingly, it is an object of the present invention 3,071,017 Patented Jan. 1, .1963

to provide an improved intermittent drive for a sequential timer.

Another object of the present invention is to provide a sequential timer drive mechanism which may be readily adapted to a wide range of consumer requirements.

Yet another object of the present invention is to provide a drive structure which precludes overstepping or over-indexing the sequence controlling cam driven there- A still further object of the present invention is to provide a sequential timer drive mechanism which may be assembled or disassembled without the use of tools.

Many other advantages, features and additional objects of the present invention will become manifest to those versed in the art upon making reference to the detailed description and to the accompanying sheets of drawings in which preferred structural embodiments incorporating the principles of the present invention are shown by way of illustrative example.

On the drawing:

FIGURE 1 is an elevational view of the sequential timer equipped with a drive mechanism provided in accordance with the principles of the present invention, the parts being partially broken away to illustrate in terior structure;

FIGURE 2 is a side view of the structure shown in FIGURE 1, being shown partly in section, and being fragmentary;

FIGURES 3 and 4 are diagrammatic representations of the operation of the novel drive mechanism incorporated in the structure shown in FIGURE 1;

FIGURE 5 is an elevational view of a modified form of the drive mechanism of FIGURE 1; and

FIGURE 6 is a side view of FIGURE 5, shown partly in cross-section.

As shown on the drawing:

The principles of this invention are particularly useful when embodied in a sequential timer assembly such as illustrated in FIGURE 1, generally indicated by the numeral 10. The timer assembly 10 includes a housing 11 having housing halves 11a and 11b which are complemental to each other and which are secured together by appropriate means such as bolt and screw assemblies 12, 13 and 14. Various electrical circuits may be connected to different electrical terminals such as 15, each of which leads to appropriate switch contacts (not shown) within the housing 11. Also within the housing 11 is a disc-like sequence cam 16 which has a series of cam tracks 17 disposed on an axially directed face thereof, and radially spaced from each other. The sequence cam 16 is rotatably supported in the housing 11 by any convenient means such as by a shaft 18 which may extend in either direction from the housing 11 to support a knob (not shown). While the cam 16 may be manually rotated by the rotation of the shaft 18, it may be automatically rotated in increments by forces applied to a series of peripheral teeth 19 carried thereon. In response to either manual or automatic rotation of the sequence cam 16, the various circuits are opened and closed in accordance with a timing or sequence program defined by the rises and falls on the various cam tracks 17. A pair of mounting pads 20 extend from either of the housing halves 11a, 11b, by which the mechanism 10 may be supported as a unit.

A plate 21 is secured to one side of the housing half cam 16 takes after each increment of movement. This adjustment thus may be utilized to insure proper coordination between the various tracks 17 as a group with respect to the switches contained Within the housing and not shown.

A conventional motor 21:: having a built-in speed reducing gear train contained in a case 22 is secured to the lower side of the plate 21 as by one or more screws 23. The gear train is operative to drive a non-circular shaft 24 which projects through the plate 21. The shaft 24 is thus supported with respect to the housing, and has an axis which is radially offset from that of the sequence cam 16, the shaft being rotatably driven by the motor 21a.

A drive cam 25 is supported on the shaft 24', the cam 25 illustrated having a non-circular axial opening corresponding to the sectional configuration of the shaft 24 so that in this embodiment, the shaft 24 and the drive cam 25 are co-rotat-able. The motor-driven cam 25 is preferably axially slidably removable from the shaft 24. The motor-driven cam 25 is provided with a peripheral track having a slow or gradual rise portion 26, and having a free fall or non-engaged cut-away portion 27. The slow rise portion 26 is utilized to store energy from the motor 21a in a spring 28, and the free fall portion 27 permits release of energy from the spring 28 to perform work, namely an incremental advance of the sequence cam 16, at a rate far in excess of that which the motor 21:: could perform such work. Cover means 29, described more fully below, are employed to retain the motor-driven cam 25 on its supporting shaft.

The motor-driven cam 25 is thus employed to operate a resiliently biased drive linkage, generally indicated by the numeral 30, which has driving engagement with the sequence cam 16. The drive linkage 30 includes a pin 31 which is rotatably mounted in the housing 11 and which extends therethrough, one end of which projects through a slot (not shown) in the plate 21 for a distance beyond such plate. The axis of the pin 31 is offset from and parallel to the rotational axes of the cams 16 and 25. The pin 31 is retained axially within the housing 11 by any convenient means, and in this embodiment, a ratchet lever 32 is rigidly secured to the pin 31 and projects through the housing 11 in a slot defined by the housing halves 11a, 11b. Thus the housing 11 acting on the lever 32 axially retains the pin '31, and the ratchet lever 32 is pivotally supported by the pin 31. An inner end or arm 33 of the lever 32 extends to a point adjacent to the teeth 19 of the sequence cam 16, and pivotally supports a driving dog 34 having a tooth engaging and camrning portion 35. A spring 36 biases the dog 34 into a position where it can engage the teeth, while a stop 37a carried on the arm 33 limits the angular movement of the dog 34 so that it does not quite bottom in the valley or root intermediate each of the teeth 19. Suitable integral retaining means is provided on the arm 33 and on the dog 34, as shown, for retaining the spring 36 thereon. When the cam 16 is manually rotated in a counter clockwise direction, the sloping surface of an approaching tooth engages a caniming surface on the portion 35 of the dog 34, thereby causing the dog 34 to compress the spring 36 and to yieldably allow the sequence cam 16 to be manually rotated. Similarly, when the arm 33 is pivoted about the pin 31 the stationary tooth 19 likewise engages the camming portion '35 of the dog 34 to allow the dog to yield and to facilitate it to pass over one tooth preparatory to driving the sequence cam in a counter clockwise direction as shown. It will thus be noted that the ratchet lever 32 has driving engagement with each of the ratchet teeth 19 one at a time.

The ratchet lever 32 has a portion 37 extending from the pin 31 between the housing halves 11a, 11b to a point outwardly of the housing 11. To this outwardly extending portion 37, there is a further portion connected substantially at right angles thereto and indicated at 38 til which extends substantially parallel to the axis of the pin 31, through an appropriate slot 39 in the plate 21. From the portion 38, a further portion 40 extends substantially parallel to the plate 21 and is adapted to receive one end of the spring 28 to be biased by the spring 28 into engagement with the plate 21, the engagement occurring between the portion 38 and the edge of the plate 21 which is located at the inner end of the slot 39.

The other end of the spring 28 is secured in an car 42, preferably comprising a struck-up portion of the plate 21. It can thus be seen that the spring 28 urges the ratchet lever '32 in a clockwise direction about the axis of the pin 31. v

The drive linkage 30 further includes a lever arm. 43 which has an aperture at one end receiving the pin 31 so that the lever arm 43 is pivotally supported on the projecting end portion of the pin 31. When the lever arm 43 has been rotated clockwise with respect to the ratchet lever 32, the lever arm 43 may be slidably removed from the pin 31. At a point intermediate the pin 31 and the distal end 44 of the lever arm 43, the side of the lever arm 43 is engaged by the edge of the portion 38 of the lever 32, so that the biased ratchet lever 32 causes the lever arm 43 to be pivoted toward the peripheral track of the motor-driven cam for engagement therewith.

The ratchet lever 32 is provided with means to restrain the lever arm 43 from being slidably removed from the pin 31. In this embodiment, the restraint is provided by an ear 45 integral with tie portion 40 so that the lever arm 43 extends intermediate the ear 45 and the portion 37. It will be appreciated that normally the lever arm 43 and the ratchet lever 32 pivot as a unit. However, if the cam 25 be removed, then the lever arm 43 can be pivoted clockwise about the pin 31 in order to clear the ear 45 for the removal of the lever arm 43.

One of the principal aspects of the instant invention is that the free fall 27 of the drive cam 25 does not extend perpendicularly to a tangent at the end thereof, and may or may not (as shown) be undercut but clears the end of the lever 43 as shown in FIGURE 1, and thereby presents a surface which the distal end of the lever arm 43 cannot engage as it is driven along the free fall 27. To this end, in this embodiment, there is provided a cam surface 46 on the distal end 44 of the lever arm 43, the cam surface 46 extending a non-uniform distance from the axis of the pin 31 so that there is a cam-to-cam engagement between a point on the end of the slow-rise portion 26 and a point on the cam surface 46 which latter point progresses along the cam surface 46, as shown in FIGURE 4, as the parts turn and pivot.

The mutually engageable points on surfaces 26 and 46 thus permit rapid pivoting of the drive linkage in a clockwise direction in response to release of stored energy in the spring means, said mutualy engageable surfaces 26 and 46 being so configured that the release of energy is partially opposed or restrained by the motor-driven cam 25. During such release of energy, force from the spring 28 is thus applied to the cam 25 at a point which is substantially fixed, and hence such force acts through a constant length moment arm from the axis of the shaft 24 whereby the retarding effect of the gearing, which normally drives the shaft 24, acts through a moment arm of constant maximum length during the advance of the main timing cam 16.

While the stored energy in the spring 28 is being released, the drive linkage 30 pivots in a clockwise direction, and the tooth engaging portion of the dog 34 thereof advances the sequence cam 16 by an increment of one tooth. Since the cam 16 has a considerable amount of inertia, and since the drive mechanism 30 is driven in a restrained manner, the acceleration applied to the sequence cam 16 is thereby limited, so that when the drive linkage 36 has pivoted clockwise to a point where the portion 38 engages the plate 21, the frictional forces acting on the sequence cam 16 are sufiiciently strong to prevent continued movement, coasting, or the like, also referred to herein as over-stepping and over-indexing. Thus the program controlled by the device is reliably maintained from a time standpoint.

In this embodiment, the cover 29 encloses the spring 28, the portion 40 of the lever 32, the lever arm 43, and the motor-driven cam 25. In addition, as best seen in FIGURE 2, the cover also is engageable with an axial face of the motor-driven cam 25 in response to any axial movement thereof to preclude its removal from the shaft 24.

In this embodiment, the cover 29 is provided with a pair of integral ears 47 which extend beneath lugs 48 integrally formed from the plate 21. The cover 29 also has a second pair of ears 49 which extend individually through apertures in the plate 21 and are then bent over as shown to hold the cover securely in place. The cover material preferably comprises a soft metal so that when the cars 49 have been straightened, the cover may be readily removed. Once this has been done, the cam 25 may be removed, then the lever arm 43 may be slidably removed, and of course the spring 28 may also be disconnected. By appropriate substitution of parts corresponding to the spring 28, the cam 25, and the lever arm 43 having the cam surface 46, different amounts of energy can be stored in the drive mechanism, and different amounts of restraint may be imposed upon its release as may be required for a particular combination of drag-producing components acting on the sequence cam 16.

The operation of the timer as a whole is now apparent. However, FIGURE 3 illustrates the relationship between the various parts which exists when the cam 25 is storing energy in the spring 28, an end of the cam surface 46 then being engageable with the slow-rise portion 26 of the cam 25. Once the free fall portion of the cam track is in partial alignment with the cam surface 46, the lever arm 43 together with the ratchet lever 32 pivots about the pin 31 in response to the energy being released by the spring 28. This produces a camming effect between a point at the end of the cam surface 26 of the drive cam 25 and the cam surface 46 of the lever arm 4-3. This is best illustrated in FIGURE 4. Thus the point where the cam 25 is engaged during energy release is defined by the intersection of the higher rise end of the surface 26 with the surface 2i7. When energy is being stored in the spring as shown in FIGURE 3, all of the clearance or backlash in the various gears of the motor gear train will be in one direction. However, when the parts take on the relationship shown in FIGURE 4, not only will the spring 28 acting through the ratchet lever 32 advance the sequence cam 16 in the direction shown, but the cam surface 46 will act against the end of the cam surface 26 of the cam 25 to positively rotate the cam through an effective lever arm of constant length to an extent where the backlash is substantially if not entirely taken up, after which the motor itself comprises an inertia element for retarding the fast drop of the lever arm 43. It is thus apparent that since acceleration of the lever arm 43 is restrained, the sequence cam 16 will be positively driven, but with limited acceleration applied thereto. It is also seen that the parts having the compensating dimensions as well as the spring 2 8 may be readily selected from an assortment thereof for characterizing a particular timer model to the requirements imposed by the customer, or for characterizing an individual unit to compensate for the various factors which have united in determining the susceptibility of the sequence cam 16 to extended inertial movement.

It is to be understood that the terms clockwise and counter clockwise as used herein are terms of reference and not of limitation.

Referring now to FIGURES 5 and 6, there is shown a further preferred embodiment of the instant invention wherein the sequential timer assembly is generally indicated by numeral 50. In this embodiment, components or parts of components which are identical to that shown in 6 FIGURE 1 have been identified by the same reference numerals.

Not all motors 21a of the embodiment shown in FIG- URES 1 and 2 that are commercially available have a gear train 22 which is capable 'of withstanding the reversely directed forces described without being susceptible to wear under prolonged operating conditions. One of the advantages of the embodiment shown in FIG- URES 5 and 6 is that by the inclusion of an additional pair of gears disposed externally to the gear train, the forces and loads on the gear train are minimized, thereby protracting the life thereof for this type of service.

Accordingly, this embodiment is provided with a plate 51 which supports a motor 52 as by screws 23, which plate is secured to the housing 11 as described before. The motor 52 has a gear train enclosed in a casing 53, the output of which comprises a motor shaft 54 extending through an opening in the plate 51. A motor pinion 55 is corotatably carried on the motor shaft '54 and is disposed :on the opposite side of the plate 51. A motordriven cam 56 having teeth 57 which mesh with the pinion 55 is rotatably supported on a shaft 58 which is secured to the plate 51. The motor-driven cam 56 is provided with two slow rise portions 59 and with two free fall portions 60. In this embodiment, the precipitous drop portions 60 optionally comprise braces which blend with the plane of the teeth 57 and which braces 60 are not engageable with anything other than the cam 56 of which they comprise an integral part. The slow rise portion 59 and the free fall portions 60 are disposed immediately adjacent to the plate 51, and the teeth 57 of the cam 56 overhang the track portions 59, 60 to comprise means for effecting a further function pointed out below. The cam 56 is also provided with an axially ex tended hub 61 which is engageable with the cover means 29.

This embodiment includes a drive linkage generally indicated at 62 which is pivotally supported for rotation about the axis of a pin 63. The linkage 62 includes a ratchet 64 provided with portions, not shown, identical to that of FIGURE 1 for rotating the disc-like sequence cam 16. The ratchet lever 64 also includes portions 37 and 38 identical to those already described, and which terminate in a further portion 65 which extends substantially parallel to the plate 51 and is adapted to receive one end of the spring 28 to be biased by the spring 28 into engagement with the plate 51, the engagement occurring between the portion 38 and the edge of the plate 51 which is located at the inner end of the slot 39.

The drive linkage 62 further includes a lever arm 66 which has an aperture at one end receiving the pin 63 so that the lever arm 66 is pivotally supported on the projecting end portion of the pin 63. With the cover means 29 removed, the lever arm 66 may be raised and slidably removed from the pin 63, which extends axially a lesser distance than the pin 31. At a point intermediate the pin 63 and the distal end 67 of the lever arm 66, the side of the lever arm 66 is provided with a projection 69, the edge of which is flatwisely engageable with the portion 38 of the lever 64, so that the biased ratchet lever 64 causes the lever arm 66 to be pivoted toward the peripheral tracks 59 of the motor driven cam 56 for engagement therewith.

The teeth 57 of the cam 56, in this embodiment, comprise an overhanging portion which is superposed with respect to the distal end 67 of the arm 66, the overhanging portion thus being engageable with the end 67 to limit the amount which that end of the arm 66 may be moved from the plate 51. The arm 66 is also provided with an axially extending hub 70 which, like the cam hub 61, is engageable with the cover means to preclude removal of the lever arm 66 from the pin 63.

With the cover means 29 removed, and with the bias from the spring 28 manually overcome, the arm 66 can be manually raised to a point where the teeth 57 engage the distal end of the arm 67 which permits the pin 63 to be disengaged from the hub 70, thereby permitting the arm 66 to be manually tilted so that the projection 69 clears the upper part 65 of the ratchet lever 64. Thus the lever arm 66 may be easily replaced for the purposes previously explained. Under like conditions, the cam 56 may be slidably removed and replaced.

As in the case of the other embodiment, the lever arm 66 is provided with a cam face 68 on its distal end 67, substantially identical in contour and function to the cam surface 46, the cam face or surface 68 also extending a non-uniform distance from the axis of the pin 63 so that there is a cam-to-cam engagement between a point on the end of each slow-rise portion 59 with a point on the cam surface 68 which progresses down the cam surface 68 as the parts turn and pivot. As previously described, this type of engagement causes the drive linkage 62 to be driven in a restrained manner due to retardation through a moment arm in the cam 56 of constant length, with the acceleration applied to the sequence cam 16 thereby limited to preclude over-stepping or over-travel thereof.

Although various minor modifications might be suggested by those versed in the art, it should be understood that I wish to embody Within the scope of the patent warranted hereon all such embodiments as reasonably and properly come Within the scope of my contribution to the art.

I claim as my invention:

1. An intermittent drive mechanism for advancing a member in a step-by-step manner comprising in combination: a rotatably mounted motor-driven cam having a peripheral track; a pivotally supported drive linkage resiliently biased toward said track and adapted to have a one-way drive connection with said member; said cam being in engagement with and operative to rock said drive linkage about an axis offset from and parallel to the rotational axis of said cam; said linkage having an elongated cam surface extending a nonuniform distance from its pivotal axis; said peripheral track having an end defined by a free fall drop, said end having a point progressively engageable with said elongated cam surface of said linkage for limiting the acceleration applied by said linkage to said member during step-by-stepadvancements thereof.

2. An intermittent drive mechanism for advancing a member in a step-by-step manner comprising in combination: a rotatably mounted motor-driven cam having a peripheral track; a pivotally supported drive linkage adapted to have a one-way drive connection with said member; said cam being engageable with and operative to rock said drive linkage about an axis offset from and parallel to the rotational axis of said cam; spring means urging said drive linkage to pivot toward said track; an arm comprising part of said linkage and having a distal end 'Which coacts with said peripheral track of said motordriven cam, said track including a slow-rise portion operative during rotation thereof to act on said arm to pivot said linkage and to simultaneously store energy in said spring means, said track having a free fall portion which enables said spring to release energy rapidly; said distal end having an elongated cam surface slidably engageable with said cam at a point at the end of said peripheral track at said free fall portion for limiting the acceleration applied by said linkage to said member as energy is released from said spring during step-by-step advancements thereof.

3. An intermittent drive mechanism for advancing a member in a step-by-step manner comprising in combination: a rotatably mounted motor-driven cam having a peripheral track; a pin supported with its axis offset from and parallel to the rotational axis of said cam; a drive linkage pivotally supported by said pin and adapted to have a one-way drive connection with said member; spring means urging said drive linkage to pivot toward said track; said drive linkage including an arm removably supported on said pin, and freely slidably and individually detachable from said drive linkage, and having a distal end which engages with said peripheral track of said motor-driven cam; said track including a slow-rise portion operative during rotation thereof to engage said arm to pivot said linkage and to simultaneously store energy in said spring means, said track having a free fall portion which enables said spring to release energy rapidly; said distal end having an elongated cam surface slidably engageable With said cam at a point at the end of said peripheral track at said free fall portion for limiting the acceleration applied by said linkage to said member as energy is released from said spring during step-by-stcp advancements thereof.

4. An intermittent drive mechanism for advancing a member in a step-by-step manner comprising in combination: a motor-driven shaft; a drive cam carried on said shaft and having a corotatable free sliding connection therewith for enabling removal of said cam individually, said cam thereby being a slidably removable motor-driven cam, and having a peripheral track; a pin supported with its axis offset from and parallel to the rotational axis of said cam; a drive linkage pivotally supported by said pin and adapted to have a one-Way drive connection with said member; spring means urging said drive linkage to pivot toward said track; said drive linkage including an arm removably supported on said pin, and freely slidably and individually detachable from said drive linkage, and having a distal end which engages with said peripheral track of said motor-driven cam, said track including a slow-rise portion operative during rotation thereof to engage said arm to pivot said linkage and to simultaneously store energy in said spring means, said track having a free fall portion which enables said spring to release energy rapidly; said distal end having an elongated cam surface slidably engageable with said cam at a point at the end of said peripheral track at said free fall portion for limiting the acceleration applied by said linkage to said member as energy is released from said spring during step-by-step advancements thereof. a

5. An intermittent drive mechanism for advancing a member in a step-by-step manner comprising in combination: a motor-driven shaft; a drive cam carried on said shaft and having a corotatable free sliding connection therewith for enabling removal of said cam individually, said cam thereby being a slidably removable motor-driven cam, and having a peripheral track; a pivotally supported drive linkage adapted to have a one-way drive connection with said member; said cam being engageable by and operative to rock said drive linkage about an axis offset from and parallel to the rotational axis of said cam; spring means urging said drive linkage to pivot toward said track; an arm comprising part of said linkage and having a distal end which coacts with said peripheral track of said motordriven cam, said track including a slow-rise portion operative during rotation thereof to act on said arm to pivot said linkage and to simultaneously store energy in said spring means, said track having a free fall portion which enables said spring to release energy rapidly; said distal end having an elongated cam surface slidably engagcable with said cam at a point at the end of said peripheral track at said free fall portion for limiting the acceleration applied by said linkage to said member as energy is released from said spring during step-by-step advancements thereof.

6. An intermittent drive mechanism for advancing a member in a step-by-step manner comprising in combination: a rotatably mounted motor-driven cam having means enabling free slidable individual removal of said cam and having a peripheral track; a pin supported with its axis offset from and parallel to the rotational axis of said cam; a drive linkage pivotally supported by said pin and adapted to have a one-Way drive connection with said member; spring means urging said drive linkage to pivot toward said track; said drive linkage including an arm removably supported on said pin, and freely slidably and individually detachable from said drive linkage, and having a distal end which engages with said peripheral track of said motor-driven cam, said track including a slow-rise portion operative during rotation thereof to act on said arm to pivot said linkage and to simultaneously store energy in said spring means, said track having a free fall portion which enables said spring to release energy rapidly; said distal end having an elongated cam surface slidably engageable with said cam at a point at the end of said peripheral track at said free fall portion for limiting the acceleration applied by said linkage to said member as energy is released from said spring during step-by-step advancements thereof.

7. An intermittent drive mechanism for advancing a member in a step-by-step manner comprising in combination: support means; a motor-driven shaft carried by said support means; a drive cam carried on said shaft and having a corotatable free sliding connection therewith for enabling removal of said cam individually, said cam thereby being a slidably removable motor-driven cam, and having a peripheral track; a pin carried by said support means in a manner where it is supported with its axis offset from and parallel to the rotational axis of said cam, said pin having an end portion projecting from said support means; a drive linkage pivotally supported by said pin and adapted to have a one-way drive connection with said member; spring means urging said drive linkage to pivot toward said track; said drike linkage including'an arm freely slidably and individually removable from and pivotally supported on said end portion of said pin, and urged by said drive linkage to pivot toward said peripheral track of said motor-driven cam for engagement therewith; said drive linkage having means normally engageable with said slidably removable arm to preclude removal of said arm from said pin; said arm having a distal end which engages with said peripheral track of said motor-driven cam, said track including a slow-rise portion operative during rotation thereof to act on said arm to pivot said linkage and to simultaneously store energy in said spring means, said track having a free fall portion which enables said spring to release energy rapidly; said distal end having an elongated cam surface slidably engageable with said cam at a point at the end of said peripheral track at said free fall portion for limiting the acceleration applied by said linkage to said member as energy is released from said spring during step-by-step advancements thereof; and means removably secured to said support means and engageable with said slidably removable motor-driven cam axially to preclude removal of said motor-driven cam from said shaft.

8. An intermittent drive mechanism for advancing a member in a step-by-step manner comprising in combination: support means; a shaft carried by said support means; a motor-driven drive cam carried on said shaft and having means enabling free slidable individual removal of said cam, said cam thereby being a slidably removable motor-driven cam, and having a peripheral track; a pin carried by said support means in a manner where it is supported with its axis offset from and parallel to the rotational axis of said cam, said pin having an end portion projecting from said support means; a drive linkage pivotally supported by said pin and adapted to have a one-way drive connection with said member; spring means urging said drive linkage to pivot toward said track; said drive linkage including an arm freely slidably and individually removable from and pivotally supported on said end portion of said pin, and urged by said drive linkage to pivot toward said peripheral track of said motor-driven cam for engagement therewith; means comprising part of one of said drive linkage and said motor-driven cam, said means being normally engageable with said slidably detachable lever arm to preclude removal of said arm from said pin; said arm having a distal end which engages with said peripheral track of said motor-driven cam, said track including a slow-rise portion operative during rotation thereof to act on said arm to pivot said linkage and to simultaneously store energy in said spring means, said track having a free fall portion which enables said spring to release energy rapidly; said distal end having an elongated cam surface slidably engageable with said cam at a point at the end of said peripheral track at said free fall portion for limiting the acceleration applied by said linkage to said member as energy is released from said spring during step-by-step advancements thereof; and means removably secured to said support means and engageable with said slidably removable motor-driven cam axially to preclude removal of said motor-driven cam from said shaft.

9. An intermittent drive mechanism for advancing a member in a step-by-step manner comprising in combination: support means; a shaft carried by said support means; a motor-driven drive cam carried on said shaft and having means enabling free slidable individual removal of said cam, said cam thereby being a slidably removable motor-driven cam, and having a peripheral track; a pin carried by said support means in a manner where it is supported with its axis offset from and parallel to the rotational axis of said cam, said pin having an end portion projecting from said support means; a drive linkage pivotally supported by said pin and adapted to have a one-way drive connection with said member; spring means urging said drive linkage to pivot toward said track; said drive linkage including an arm freely slidably and individually removable from and pivotally supported on said end portion of said pin, and urged by said drive linkage to pivot toward said peripheral track of said motor-driven cam for engagement therewith; said arm having a distal end which engages with said peripheral track of said motor-driven cam, said track including a slow-rise portion operative during rotation thereof to act on said arm to pivot said linkage and to simultaneously store energy in said spring means, said track having a free fall portion which. enables said spring to release energy rapidly; said distal end having an elongated cam surface slidably engageable with said cam at a point at the end of said peripheral track at said free fall portion for limiting the acceleration applied by said linkage to said member as energy is released from said spring during step-by-step advancements thereof; and means removably secured to said support means and engageable with both said motor-driven cam and said lever arm in a direction to preclude their removal from said shaft and from said pin respectively.

10. An intermittent drive mechanism for advancing a member in a step-by-step manner comprising in combination: a rotatably mounted motor-driven cam having a peripheral track with a free-fall drop; a pivotally supported drive linkage resiliently biased toward said track and adapted to have a one-way drive connection with said member; said cam being engaged by and operative to rock said drive linkage about an axis offset from and parallel to the rotational axis of said cam; said linkage including an arm extending from the pivotal axis of said linkage, said arm having a distal end comprising a cam surface engageable with said peripheral track of said motor-driven cam and extending a non-uniform distance from said pivot-a1 axis, said track having a substantially constant point engageable with said distal end cam surface of said arm along the length thereof during driving of said member for limiting the acceleration applied by said linkage to said member during step-by-step advancements thereof.

11 E2 UNITED STATES PATENTS 2,703,347 Constantine 2 Mar. 1, 1955 1,622,027 Couchman et a1. Mar. 22, 1927 2,803,715 Guth 20, 7 2,203,831 Bassett July 23, 1940 2,808,207 Dorfner Oct 1, 195 7 2,482,434 Poole Sept, 20, 1949 2,869,375 Lewis Jan. 20, 1959 2,649,018 Schnetzer Aug. 18, 1953 5 2,877,317 Euler et a1. Mar. 10, 1959 2,680,378 Moe June 8, 1954 2,917,933 Harris Dec. 22, 1959 

7. AN INTERMITTENT DRIVE MECHANISM FOR ADVANCING A MEMBER IN A STEP-BY-STEP MANNER COMPRISING IN COMBINATION: SUPPORT MEANS; A MOTOR-DRIVEN SHAFT CARRIED BY SAID SUPPORT MEANS; A DRIVE CAM CARRIED ON SAID SHAFT AND HAVING A COROTATABLE FREE SLIDING CONNECTION THEREWITH FOR ENABLING REMOVAL OF SAID CAM INDIVIDUALLY, SAID CAM THEREBY BEING A SLIDABLY REMOVABLE MOTOR-DRIVEN CAM, AND HAVING A PERIPHERAL TRACK; A PIN CARRIED BY SAID SUPPORT MEANS IN A MANNER WHERE IT IS SUPPORTED WITH ITS AXIS OFFSET FROM AND PARALLEL TO THE ROTATIONAL AXIS OF SAID CAM, SAID PIN HAVING AN END PORTION PROJECTING FROM SAID SUPPORT MEANS; A DRIVE LINKAGE PIVOTALLY SUPPORTED BY SAID PIN AND ADAPTED TO HAVE A ONE-WAY DRIVE CONNECTION WITH SAID MEMBER; SPRING MEANS URGING SAID DRIVE LINKAGE TO PIVOT TOWARD SAID TRACK; SAID DRIKE LINKAGE INCLUDING AN ARM FREELY SLIDABLY AND INDIVIDUALLY REMOVABLE FROM AND PIVOTALLY SUPPORTED ON SAID END PORTION OF SAID PIN, AND URGED BY SAID DRIVE LINKAGE TO PIVOT TOWARD SAID PERIPHERAL TRACK OF SAID MOTOR-DRIVEN CAM FOR ENGAGEMENT THEREWITH; SAID DRIVE LINKAGE HAVING MEANS NORMALLY ENGAGEABLE WITH SAID SLIDABLY REMOVABLE ARM TO PRECLUDE REMOVAL OF SAID ARM FROM SAID PIN; SAID ARM HAVING A DISTAL END WHICH ENGAGES WITH SAID PERIPHERAL TRACK OF SAID MOTOR-DRIVEN CAM, SAID TRACK INCLUDING A SLOW-RISE PORTION OPERATIVE DURING ROTATION THEREOF TO ACT ON SAID ARM TO PIVOT SAID LINKAGE AND TO SIMULTANEOUSLY STORE ENERGY IN SAID SPRING MEANS, SAID TRACK HAVING A FREE FALL PORTION WHICH ENABLES SAID SPRING TO RELEASE ENERGY RAPIDLY; SAID DISTAL END HAVING AN ELONGATED CAM SURFACE SLIDABLY ENGAGEABLE WITH SAID CAM AT A POINT AT THE END OF SAID PERIPHERAL TRACK AT SAID FREE FALL PORTION FOR LIMITING THE ACCELERATION APPLIED BY SAID LINKAGE TO SAID MEMBER AS ENERGY IS RELEASED FROM SAID SPRING DURING STEP-BY-STEP ADVANCEMENTS THEREOF; AND MEANS REMOVABLY SECURED TO SAID SUPPORT MEANS AND ENGAGEABLE WITH SAID SLIDABLY REMOVABLE MOTOR-DRIVEN CAM AXIALLY TO PRECLUDE REMOVAL OF SAID MOTOR-DRIVEN CAM FROM SAID SHAFT. 